Specification Sheet For VAO

Filters а аа

а а аR а а а а а а аred filter, broad band

а а аGаа а а а а а аgreen filter, broad band

а а аBаа а а а а а аblue filter, broad band

Halpha а а а а аHalpha line, narrow band: 656 nm

а а Oаа а а а а а аOxygen III line, narrow band: 500.7 nm

а а аIаа а а а а а аInfrared, broad band

а а N а а а а а а аNo filter, broad band


Magnitude Limits

18th or 19th magnitude stars

Field of View

42аarc minutesаby 42аarc minutes

Resolution

The resolution of VAO is 0.62аarc secondsаper pixel but in practice, the actual resolution is dependent on how clear a night it is. For example,аon a good night is about 2 arcseconds and 5 arcseconds on a poor night.

Exposure Times

As a general guide, extended objects such as galaxies and nebulae should be imaged with a 60 second exposures for broad band (N,L,R,G,B,W) filters аand 120 seconds for narrow band (H,O,S) filters. (Anаimportantаexception to this rule is M42 and M 43, which will need 5 second exposures.) Star clusters should be imaged with 5 to 10 second exposures. аEach solar system object is different.аIn general, stars that you can see with your naked eye are too bright to be imaged using VAO.

ай 2017 University of Iowa